Friday, August 24, 2012

Part 1 - Sitting Too Close To Your 3D TV Will Make You Go Blind?

Well,
not really. One of several things my Mom said would make me go blind is
sitting too close to our black and white standard definition 2DTV many years
ago. Today the question is... how close or how far from a modern 3D display
device should a person sit to achieve a satisfying, immersive experience?

If
you read the literature as most early adopters do, you’ll find conflicting
information on the proper way to set up your new 3DTV home theater to achieve
an optimal experience. Unfortunately, to some people, it’s all too
intimidating to bother with or they end up calling the retail store “experts”
to properly set-up their home theater environment.

In
my opinion, you can forget about textbook advice on the “proper” distance to
sit in a 3D home theater environment or for that matter, where to sit in a
movie theater. In my blog, "People Who Hate 3D Movies Should Have Their Eyes
Examined," I discuss how no two people see 3D in quite the same way
and that much of the difference depends on the balance of visual acuity between
a person’s two eyes as well as the accuracy of their gaze, such that the field
of view of each eye falls onto the proper retinal location. In this
context, most of the technical considerations for the proper “zone of comfort”
fall away. The real question is what’s most comfortable to the individual
given the quality of their vision and/or their form of optical correction and
also what is the type of immersive experience the individual is trying to
achieve.

The
Rule of Thumb is That There are No Rules.

You’ll
often read that the proper distance to sit in a 3D movie theater is 1.5X the
height of the screen. I guess that means that if you find yourself
outside of the ‘sweet spot’ of the theater you might as well forget about
getting the maximum experience from the movie. Maybe taking a page from
the latest airline playbook where some are charging for aisle or window seats,
theaters should start charging extra for the 'preferred' center seats in the row
that’s 1.5X from the screen.

When
I‘m in a 3D movie theater, I typically sit in the middle/center of the
auditorium. I prefer not to sit too close to the screen, nor do I like to
sit too far to one side of the screen. In many of the new luxury theaters, like
Cinepolis, all of the seats are adequately centered on the screen. In
other theaters, sitting too far to one side of the screen can negatively affect
the 3D experience because each eye receives a skewed perspective of
parallax. However, no matter what type of theater I go to, there are
seats that are too close for my comfort. But that’s just me. Some
people feel that the best seats are as close to the screen as possible so they
can get what they consider to be a ‘full’ immersive experience. Indeed, there
are some people who expect an IMAX type experience in the first row of a
theater where their entire field of view is the screen. And that's their
personal preference. However, typically, the closer you sit in a theater
the more the 3D effect tends to diminish. If you are sitting in the front
row of a theater and an object appears to be 50% of the distance between
you and the screen, that same object will also appear to be 50% of the distance
between you and the screen even if you're sitting in the back of the
theater. But of course 50% of the distance between you and the front
seat relative to 50% of the distance between you and the back of the theater
creates two different types of immersive experiences. In the later, the
entire volume of the theater comes into play. Of course, the farther you
move back from the screen, the more distortion there is in the image, where a
round ball is no longer round but elongated, but the average moviegoer will not
notice. However, of greater importance, the closer to the screen that you
sit the more likely your eyes will tire from the strain that comes from
decoupling accommodation and convergence. You see, watching a 3D movie is
very different than the way we experience the third dimension in our every day
lives. In my blog, “Engaged in2D Movies and Immersed in 3D Movies,” I explain
this difference and point out how physiologically unnatural a 3D movie is to
our binocular vision. That doesn’t mean it’s bad. It’s just
different. In conclusion, the best place to sit in a 3D theater is where
you, personally achieve the most satisfying 3D experience, keeping in mind that
sitting too close to the screen places demands on our binocular vision that can
cause discomfort and/or headaches. Thanks Mom.

It’s
a shame that some people give up on stereo simply because their first
experience in a 3D theater was uncomfortable. Maybe that’s why some film
critics complain that the 3D was horrible or added nothing to the film, or
worse, that it detracted from the film. Maybe, in addition to visiting
their optometrist, as I’ve suggested before, they might also simply need to
adjust their seating location.

There
are, of course other things that can add to discomfort in theater, like a
terrible story line, horrible acting, poor directing, etc. You know the
drill. But as far as 3D is concerned, unless the movie is badly shot or poorly
converted, sitting further away from the screen will often help mitigate most
physical complaints.

My
Home Entertainment Theater

When
I’m in my home entertainment center I prefer to watch 3D Blu-ray movies with
the lights off to simulate the theater experience. But, I don’t sit
6 feet from the screen as we’re often instructed in the literature.
Instead, I crank up the 5.1 and sit as far back from my passive, 55’ LG screen
as possible. Again, that’s just me. Of course in sitting so far back from
the TV, I achieve a relatively narrow viewing angle of the screen, but it
allows me to take in the entire screen, which is my preference. And while
taking in the entire screen means that the screen edges become part of my field
of view, in my dark man-cave that’s not an issue. It does not detract from my
suspension of disbelief.

If
I sit as far back as 15 feet from my 3DTV (which takes me out onto the patio
watching the movie through the French doors), the snow in Scorsese’s’ Hugo
seems to engulf the entire room in front of me. To me, being immersed
under those conditions is a visual experience like no other. In fact, I
enjoy Hugo much more in my home theater than I did the five times I saw it in
on the big screen. Can you tell I love that film?

Floating
Windows

The
only time my preferred narrow field of view of the screen becomes an issue is
when a movie is released in Blu-ray without floating windows. Floating windows are an adjustment to the edges of the
screen that filmmakers typically apply in post-production to compensate for
what we call 'edge violations'. An edge violation occurs when an object
that with negative parallax (coming out of the screen), breaks one of the edges
of the screen (in this case, edges are referred to as the window) such that one
of our eyes sees more of the object than the other. Our peripheral vision
registers this as unnatural because if the object is in front of the screen it
cannot also be in back of the screen. This creates a cognitive disconnect
that cannot be resolved by our brains, causing a form of “brain-pain” called
‘ocular rivalry’—when our two eyes compete to resolve the conflict based on
their different and conflicting inputs. When this occurs our brain tries in
vane to reconcile the discontinuity between the images in each eye, causing a
type of double image at the edge of the screen that can be uncomfortable to
view. Floating windows are an adjustment to the edge of the movie frame
that’s typically applied shot by shot to eliminate this rivalry between our two
eyes in the event of edge violations. By moving the edge of the frame in
one eye so that the double image at the edge disappears, both eyes will be
seeing the same amount of the object but the object will appear slightly behind
the screen rather than in front of it. It’s called a floating window because
the window adjustment floats in and out from shot to shot, and even within a
single shot floating windows will sometimes be animated in and out to better
achieve a more comfortable stereo effect.

There
are some film directors who don’t believe in applying floating windows.
I’ve heard some say that, “if the audience is paying attention to the edges of
the screen then I haven’t done my job in directing their attention to the story
point in the shot.” What these directors don’t realize is that people enjoy
watching 3D movies in many different ways. To me, floating windows are an
essential part of 3D moviemaking because no matter where you sit in a movie
theater or home theater, unless your nose is pressed up against the screen,
edge violations are inevitably perceived by our peripheral vision and can cause
discomfort. Edge violations are simply contrary to what our brains
anticipate and will inevitably take the viewer out of the moment. It’s
particularly important to me because I prefer to sit back from the screen,
which always exposes the edges of the 3DTV, and while I tend to follow the
convergence intended by the filmmaker, extreme negative parallax at the edges
(objects in front of the screen, but cut in half by the edge of the TV) without
floating windows inevitably causes discomfort. However, when floating
windows are skillfully applied by the filmmaker, the edges melt away and my
experience is all encompassing, even though the screen takes up only a narrow
portion of my field of view.

The
Bottom Line

I believe there are no hard and fast rules to the ‘proper’
viewing of a 3D movie. Theatergoers and home theater enthusiasts should
simply experiment with proper viewing angles and distances to find the optimum
3D experience for themselves.

In
Part 2 of this topic, I’ll relay an interesting experience I had at 3D-Con, the
38th National Stereoscopic Association Conference. A conference
where the attendees were extremely knowledgeable stereo photographers and
where I learned more than I had bargained for regarding ‘proper’ viewing
distances.

Followers

Barry B. Sandrew, Ph.D.

Founder - Graffiti Video, Inc.

BIOGRAPHY

This is a series of blogs by Barry Sandrew, Ph.D., an internationally recognized inventor, digital imaging expert and visual effects pioneer. Dr. Sandrew is founder of three visual effects facilities that were among the largest and most prolific production studios in Hollywood. Over the past three decades he has been and continues to be instrumental in evolving the entertainment Industry's digital standards and processes in feature filmmaking.

Sandrew earned his doctorate in neuroscience from SUNY at Stony Brook. After winning a 2 year NIH Fellowship at Columbia University, College of Physicians & Surgeons, he joined Harvard Medical School/MGH as staff Neuroscientist. In 1987, Sandrew left his academic and scientific career to found American Film Technologies (AFT) where he invented the first all digital process for colorizing black and white feature films.

At AFT he also invented a paperless animation process used to produce episodic animation for Fox Children's TV and a digital ink & paint and compositing pipeline that produced Spielberg's first digital animated feature film, "We're Back: A Dinosaur Story." Sandrew took AFT public while converting hundreds of movies for clients such as Turner, Disney, Warner Bros., Fox, Gaumont, TF1, ABC, and CBS, among many others.

In 1993 Barry Sandrew left American Film Technologies to co-found Lightspan, an animation and production edutainment studio that grew into one of the largest educational software companies in the U.S., marketing into entire school districts around the country. Lightspan ultimately went public and was later acquired by Plato Learning.

In 2000, Sandrew founded Legend Films, re-inventing colorization and a proprietary film restoration process using the latest in digital imaging technology. Over the course of the next 7 years, Legend Films converted to color approximately 145 black & white films as well as several TV series. Legend Films also produced visual effects for Scorsese's "The Aviator", HBO's "Entourage" and other high profile TV and film projects.

In 2007, with Jim Cameron's game changing "Avatar 3D" scheduled for a 2009 release, Sandrew leveraged his proprietary colorization pipeline, redirecting his company's entire R&D focus to embrace 2D-to-3D conversion and changing the company's name to Legend3D. Since 2010, Legend3D has lead the competitive field, producing 3D conversion and visual effects on over 35 of the highest performing box office tentpole films of the past 6 years.

In 2014, Dr. Barry Sandrew left Legend3D to focus on new immersive and web based media technologies as well his non-profit and for-profit board positions. He is consultant to Fortune 500 companies re: mobile 3D-sensing and motion tracking technology that he considers precursors to augmented reality. Most recently, he is Co-Founder and President/CEO of Graffiti Video, Inc. a company that is redefining the curation of web based media.